SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '45e198c86903f7c2fca2a508fbbfb600c86817614d2d91e6a5797582f3fe40e8' 
  AND token = 'gU5NLKCJwqPAdjVDEYbPBfQ6gKD1b/ZJ4lRFLqbh2Fs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}